diff --git a/src/ui/theme.c b/src/ui/theme.c
index b19cfbf..9ecba5b 100644
--- a/src/ui/theme.c
+++ b/src/ui/theme.c
@@ -3501,6 +3501,8 @@ meta_draw_op_draw_with_env (const MetaDrawOp    *op,
                   {
                     cairo_set_line_cap (cr, CAIRO_LINE_CAP_SQUARE);
                   }
+                cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
+
                 cairo_move_to (cr, x1 + .5, y1 + .5);
                 cairo_line_to (cr, x2 + .5, y2 + .5);
               }
